The invention relates to a method and apparatus for depositing or applying a paint to an outer peripheral portion of shell such as is associated with a brake booster which is formed by staking or caulking a pair of cylindrical or circular members together.
A shell as used in a brake booster generally comprises a cup-shaped member or a cylindrical member having a closed bottom and a disc-shaped or dish-shaped member, which are coated and dried before they are assembled together and which are then disposed in abutment against each other so that a generally circular peripheral portion of the abutting members are subject to a shearing action, thus staking both members together.
It will be noted that a portion which has been subjected to a shear-staking operation has its metal exposed which may cause rust. Accordingly, a paint is applied to provide an anti-rust treatment, which has been performed manually in the prior art practice. This results in a degraded operational efficiency and presents difficulty in achieving a uniform coating.